1. Field of the Invention
The present invention relates to closure means for structural members such as doors, windows, truck beds and the like and, more specifically, it relates to such an assembly which is easy to install and may sustain impact loads with minimum structural damage.
2. Description of the Prior Art
It has been known for numerous structural usages to provide various forms of movable closures such as doors and windows, for example, including those which may be subjected to frequent use and abuse as in an industrial or commercial environment.
It has also been known to provide such doors with closure members made of flexible materials which may be received on and released from a motorized reel so as to open and close the doors. One of the problems with industrial doors of this type is that they are frequently subjected to undesired high impact loads which do structural damage to the door, the door frames, or both.
U.S. Pat. No. 550,412 discloses a means for clamping and unclamping screen material between framing members by employing pins which slide in angularly disposed slots moving in a plane generally perpendicular to the plane of the screen material U.S. Pat. No. 1,961,383 discloses window screens having pins moving in angularly disposed slots which serve as stop members.
A clamping mechanism for a window screen disclosed in U.S. Pat. No. 1,892,001.
U.S. Pat. No. 2,886,103 discloses a retractable system for windows wherein a cam slot serves to provide clamping once the closure is in place.
U.S. Pat. No. 2,594,910 discloses a roll-up type cover for trucks and trailers. U.S. Pat. No. 2,584,014 discloses a removable truck top.
U.S. Pat. No. 4,825,921 discloses a roll-up material, such as a screen, which has either formed within or secured to its edges supporting elements which are said to be composed of relatively thin material. These elements are engaged in guide rails. It also discloses the use of intermediate reinforcing members disposed within the web. In the preferred form, the supporting elements are of concave shape.
U.S. Pat. No. 4,766,941 discloses the use of a motor in operating a roller shade.
U.S. Pat. No. 4,649,981 discloses fabric having a plurality of flaps which hold the margins in the desired position.
A window screen having projecting tabs which are adapted to move in a slot is disclosed in U.S. Pat. No. 618,831. U.S. Pat. No. 1,425,484 also discloses a screen member having portions which ride in a track.
U.S. Pat. No. 1,673,326 discloses a spring biased tensioning mount for applying tension to a screen.
U.S. Pat. No. 1,387,452 discloses a window screen having a roller cam which may be rotated by means of an operating handle in order to cam the screen fabric against the track wall.
U.S. Pat. No. 4,825,921 discloses a roll-up material, such as a screen which has either formed within or secured to its edges supporting element which are said to be composed of relatively thin resilient material and are engaged in guide rails.
In spite of these previously known systems, there remains a need for an improved closure system for structural members which will resist undesired damage, provide effective sealing, and function in an efficient manner under a wide variety of operating conditions.